Patent literature 1: JP H08-191600 A
Conventionally, a current control apparatus controls current supplied to an electric motor through an inverter. For example, patent literature 1 controls voltages of a d-axis and a q-axis, so that the sum of squares of a d-axis voltage command value and a q-axis voltage command value becomes a constant value and an output voltage of the inverter is not saturated.
The inventers of the present disclosure have found the following.
As described in patent literature 1, when the d-axis voltage command value and the q-axis voltage command value are controlled so that the sum of the squares of the d-axis voltage command value and the q-axis voltage command value is constant, the q-axis voltage command value may change according to a change of the d-axis voltage command value. When the q-axis command value changes, torque of an electric motor may change and noise and vibration may increase.